Nanomaterials

9 pages, 4295 KiB

Open AccessArticle

Large-Scale Green Method for Synthesizing Ultralong Uniform Tellurium Nanowires for Semiconductor Devices

by Zhiyi Lyu, Mose Park, Yanjin Tang, Hoon Choi, Seung Hyun Song and Hoo-Jeong Lee

Nanomaterials 2024, 14(20), 1625; https://doi.org/10.3390/nano14201625 - 10 Oct 2024

This study presents a large-scale green approach for synthesizing ultralong tellurium nanowires with diameters around 13 nm using a solution-based method. By adjusting key synthesis parameters such as the surfactant concentration, temperature, and reaction duration, we achieved high-quality, ultralong Te NWs. These nanowires [...] Read more.

This study presents a large-scale green approach for synthesizing ultralong tellurium nanowires with diameters around 13 nm using a solution-based method. By adjusting key synthesis parameters such as the surfactant concentration, temperature, and reaction duration, we achieved high-quality, ultralong Te NWs. These nanowires exhibit properties suitable for use in semiconductor applications, particularly when employed as channel materials in thin-film transistors, displaying a pronounced gate effect with a high switch of up to 10⁴ and a mobility of 0.9 cm² V⁻¹s⁻¹. This study underscores the potential of solvent-based methods in synthesizing large-scale ultralong Te NWs as a critical resource for future sustainable nanoelectronic devices. Full article

(This article belongs to the Special Issue Recent Advances in Nanowires and Superconductors (Second Edition))

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16 pages, 2159 KiB

Open AccessArticle

Double-Layer Metasurface Integrated with Micro-LED for Naked-Eye 3D Display

by Qinyue Sun, Zhenhuan Tian, Chuangcheng Xu, Angsu Yu, Feng Li and Feng Yun

Nanomaterials 2024, 14(20), 1624; https://doi.org/10.3390/nano14201624 - 10 Oct 2024

Abstract

Naked-eye 3D micro-LED display combines the characteristics of 3D display with the advantages of micro-LED. However, the 3D micro-LED display is still at the conceptual stage, limited by its intrinsic emission properties of large divergence angle and non-coherence, as well as difficulties in [...] Read more.

Naked-eye 3D micro-LED display combines the characteristics of 3D display with the advantages of micro-LED. However, the 3D micro-LED display is still at the conceptual stage, limited by its intrinsic emission properties of large divergence angle and non-coherence, as well as difficulties in achieving large viewing angles with high luminous efficiency. In this work, we propose a double-layer metasurface film integrating functions of collimation with multiple deflections, constituting a micro-LED naked-eye 3D display system. The system is characterized through numerical simulations using the 3D finite-difference time-domain method. The simulation results show that the double-layer metasurface film restricts 90% of the emitted light of the micro-LED to the vicinity of the 0° angle, improving its spatial coherence. Subsequently, a large-angle, low-crosstalk outgoing from −45° to 45° is achieved, while providing a deflection efficiency of over 80% and a pixel density of up to 605. We believe this design provides a feasible approach for realizing naked-eye 3D micro-LED displays with a large field of view, low crosstalk, and high resolution. Full article

(This article belongs to the Special Issue Semiconductor Nanomaterials for Optoelectronic Applications)

19 pages, 7160 KiB

Open AccessArticle

Optical, Photophysical, and Electroemission Characterization of Blue Emissive Polymers as Active Layer for OLEDs

by Despoina Tselekidou, Kyparisis Papadopoulos, Konstantinos C. Andrikopoulos, Aikaterini K. Andreopoulou, Joannis K. Kallitsis, Stergios Logothetidis, Argiris Laskarakis and Maria Gioti

Nanomaterials 2024, 14(20), 1623; https://doi.org/10.3390/nano14201623 - 10 Oct 2024

Abstract

Polymers containing π-conjugated segments are a diverse group of large molecules with semiconducting and emissive properties, with strong potential for use as active layers in Organic Light-Emitting Diodes (OLEDs). Stable blue-emitting materials, which are utilized as emissive layers in solution-processed OLED devices, are [...] Read more.

Polymers containing π-conjugated segments are a diverse group of large molecules with semiconducting and emissive properties, with strong potential for use as active layers in Organic Light-Emitting Diodes (OLEDs). Stable blue-emitting materials, which are utilized as emissive layers in solution-processed OLED devices, are essential for their commercialization. Achieving balanced charge injection is challenging due to the wide bandgap between the HOMO and LUMO energy levels. This study examines the optical and photophysical characteristics of blue-emitting polymers to contribute to the understanding of the fundamental mechanisms of color purity and its stability during the operation of OLED devices. The investigated materials are a novel synthesized lab scale polymer, namely poly[(2,7-di(p-acetoxystyryl)-9-(2-ethylhexyl)-9H-carbazole-4,4′-diphenylsulfone)-co-poly(2,6-diphenylpyrydine-4,4′-diphenylsulfone] (CzCop), as well as three commercially supplied materials, namely Poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO), poly[9,9-bis(2′-ethylhexyl) fluorene-2,7-diyl] (PBEHF), and poly (9,9-n-dihexyl-2,7-fluorene-alt-9-phenyl-3,6-carbazole) (F6PC). The materials were compared to evaluate their properties using Spectroscopic Ellipsometry, Photoluminescence, and Atomic Force Microscopy (AFM). Additionally, the electrical characteristics of the OLED devices were investigated, as well as the stability of the electroluminescence emission spectrum during the device’s operation. Finally, the determined optical properties, combined with their photo- and electro-emission characteristics, provided significant insights into the color stability and selectivity of each material. Full article

(This article belongs to the Special Issue Photofunctional Nanomaterials and Nanostructures)

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11 pages, 3212 KiB

Open AccessArticle

Ultrastable and Low-Threshold Two-Photon-Pumped Amplified Spontaneous Emission from CsPbBr₃/Ag Hybrid Microcavity

by Shulei Li, Yatao Zhang, Zhiran Zhao, Shiyi Cheng, Zixin Li, Yuanyuan Liu, Quantong Deng, Jun Dai, Yunbao Zheng and Zhenxu Lin

Nanomaterials 2024, 14(20), 1622; https://doi.org/10.3390/nano14201622 - 10 Oct 2024

Abstract

Halide perovskite materials have garnered significant research attention due to their remarkable performance in both photoharvesting photovoltaics and photoemission applications. Recently, self-assembled CsPbBr₃ superstructures (SSs) have been demonstrated to be promising lasing materials. In this study, we report the ultrastable two-photon-pumped amplified [...] Read more.

Halide perovskite materials have garnered significant research attention due to their remarkable performance in both photoharvesting photovoltaics and photoemission applications. Recently, self-assembled CsPbBr₃ superstructures (SSs) have been demonstrated to be promising lasing materials. In this study, we report the ultrastable two-photon-pumped amplified stimulated emission from a CsPbBr₃ SS/Ag hybrid microcavity with a low threshold of 0.8 mJ/cm² at room temperature. The experimental results combined with numerical simulations show that the CsPbBr₃ SS exhibits a significant enhancement in the electromagnetic properties in the hybrid microcavity on Ag film, leading to the uniform spatial temperature distribution under the irradiation of a pulsed laser, which is conducive to facilitate the recrystallization process of the QDs and improve their structural integrity and optical properties. This study provides a new idea for the application of CsPbBr₃/Ag hybrid microcavity in photonic devices, demonstrating its potential in efficient optical amplification and upconversion lasers. Full article

(This article belongs to the Special Issue Nanostructured Materials for Photonic and Plasmonic Applications)

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13 pages, 3477 KiB

Open AccessArticle

Facile Preparation of Three-Dimensional Cubic MnSe₂/CNTs and Their Application in Aqueous Copper Ion Batteries

by Junjun Wang, Linlin Tai, Wei Zhou, Han Chen, Jingxiong Liu and Shaohua Jiang

Nanomaterials 2024, 14(20), 1621; https://doi.org/10.3390/nano14201621 - 10 Oct 2024

Abstract

Transition metal sulfide compounds with high theoretical specific capacity and excellent electronic conductivity that can be used as cathode materials for secondary batteries attract great research interest in the field of electrochemical energy storage. Among these materials, MnSe₂ garners significant interest from [...] Read more.

Transition metal sulfide compounds with high theoretical specific capacity and excellent electronic conductivity that can be used as cathode materials for secondary batteries attract great research interest in the field of electrochemical energy storage. Among these materials, MnSe₂ garners significant interest from researchers due to its unique three-dimensional cubic structure and inherent stability. However, according to the relevant literature, the performance and cycle life of MnSe₂ are not yet satisfactory. To address this issue, we synthesize MnSe₂/CNTs composites via a straightforward hydrothermal method. MnSO₄·H₂O, Se, and N₂H₄·H₂O are used as reactants, and CNTs are incorporated during the stirring process. The experimental outcomes indicate that the fabricated electrode demonstrates an initial discharge specific capacity that reaches 621 mAh g⁻¹ at a current density of 0.1 A g⁻¹. Moreover, it exhibits excellent rate capability, delivering a discharge specific capacity of 476 mAh g⁻¹ at 10 A g⁻¹. The electrode is able to maintain a high discharge specific capacity of 545 mAh g⁻¹ after cycling for 1000 times at a current density of 2 A g⁻¹. The exceptional electrochemical performance of the MnSe₂/CNTs composites can be ascribed to their three-dimensional cubic architecture and the 3D CNT network. This research aids in the progression of aqueous Cu-ion cathode materials with significant potential, offering a viable route for their advancement. Full article

(This article belongs to the Special Issue The Interaction of Electron Phenomena on the Mesoscopic Scale)

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18 pages, 7776 KiB

Open AccessArticle

Eco-Friendly Facile Conversion of Waste Eggshells into CaO Nanoparticles for Environmental Applications

by Kathalingam Adaikalam, Sajjad Hussain, Periasamy Anbu, Arulmozhi Rajaram, Iyyakkannu Sivanesan and Hyun-Seok Kim

Nanomaterials 2024, 14(20), 1620; https://doi.org/10.3390/nano14201620 - 10 Oct 2024

Abstract

Amongst the many types of food waste, eggshells contain various minerals and bioactive materials, and they can become hazardous if not properly disposed of. However, they can be made useful for the environment and people by being converted to environmentally friendly catalytic materials [...] Read more.

Amongst the many types of food waste, eggshells contain various minerals and bioactive materials, and they can become hazardous if not properly disposed of. However, they can be made useful for the environment and people by being converted to environmentally friendly catalytic materials or environmental purification agents. Simple calcination can enhance their properties and thereby render them suitable for catalytic and environmental applications. This work aimed to prepare CaO from waste eggshells and examine its effectiveness in photocatalytic pollution remediation, electrocatalytic activity, optical sensing, and antibacterial activities. As opposed to other techniques, this calcination process does not require any chemical reagents due to the high purity of CaCO₃ in eggshells. Calcium oxide nanoparticles were prepared by subjecting waste eggshells (ES) to high-temperature calcination, and the synthesized CaO nanoparticles were characterized for their structural, morphological, chemical, optical, and other properties. Furthermore, their photocatalytic degradation of methylene blue dye and antibacterial efficiency against Escherichia coli and Staphylococcus aureus were investigated. It was found that the green-converted CaO can be efficiently used in environmental applications, showing good catalytic properties. Full article

(This article belongs to the Special Issue Magnetization and Magnetic Disorder at the Nanoscale)

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15 pages, 3709 KiB

Open AccessArticle

Palladium-Functionalized Nanostructured Nickel–Cobalt Oxide as Alternative Catalyst for Hydrogen Sensing Using Pellistors

by Olena Yurchenko, Mike Benkendorf, Patrick Diehle, Katrin Schmitt and Jürgen Wöllenstein

Nanomaterials 2024, 14(20), 1619; https://doi.org/10.3390/nano14201619 - 10 Oct 2024

Abstract

To meet today’s requirements, new active catalysts with reduced noble metal content are needed for hydrogen sensing. A palladium-functionalized nanostructured Ni_0.5Co_2.5O₄ catalyst with a total Pd content of 4.2 wt% was synthesized by coprecipitation to obtain catalysts with [...] Read more.

To meet today’s requirements, new active catalysts with reduced noble metal content are needed for hydrogen sensing. A palladium-functionalized nanostructured Ni_0.5Co_2.5O₄ catalyst with a total Pd content of 4.2 wt% was synthesized by coprecipitation to obtain catalysts with an advantageous sheet-like morphology and surface defects. Due to the synthesis method and the reducible nature of Ni_0.5Co_2.5O₄ enabling strong metal-metal oxide interactions, the palladium was highly distributed over the metal oxide surface, as determined using scanning transmission electron microscopy and energy-dispersive X-ray investigations. The catalyst tested in planar pellistor sensors showed high sensitivity to hydrogen in the concentration range below the lower flammability limit (LFL). At 400 °C and in dry air, a sensor response of 109 mV/10,000 ppm hydrogen (25% of LFL) was achieved. The sensor signal was 4.6-times higher than the signal of pristine Ni_0.5Co_2.5O₄ (24.6 mV/10,000 ppm). Under humid conditions, the sensor responses were reduced by ~10% for Pd-functionalized Ni_0.5Co_2.5O₄ and by ~27% for Ni_0.5Co_2.5O₄. The different cross-sensitivities of both catalysts to water are attributed to different activation mechanisms of hydrogen. The combination of high sensor sensitivity to hydrogen and high signal stability over time, as well as low cross-sensitivity to humidity, make the catalyst promising for further development steps. Full article

(This article belongs to the Special Issue Nanostructured Materials in Gas Sensing Applications)

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46 pages, 4934 KiB

Open AccessReview

Silver Nanoparticles in Therapeutics and Beyond: A Review of Mechanism Insights and Applications

by Furkan Eker, Hatice Duman, Emir Akdaşçi, Anna Maria Witkowska, Mikhael Bechelany and Sercan Karav

Nanomaterials 2024, 14(20), 1618; https://doi.org/10.3390/nano14201618 - 10 Oct 2024

Abstract

Silver nanoparticles (NPs) have become highly promising agents in the field of biomedical science, offering wide therapeutic potential due to their unique physicochemical properties. The unique characteristics of silver NPs, such as their higher surface-area-to-volume ratio, make them ideal for a variety of [...] Read more.

Silver nanoparticles (NPs) have become highly promising agents in the field of biomedical science, offering wide therapeutic potential due to their unique physicochemical properties. The unique characteristics of silver NPs, such as their higher surface-area-to-volume ratio, make them ideal for a variety of biological applications. They are easily processed thanks to their large surface area, strong surface plasmon resonance (SPR), stable nature, and multifunctionality. With an emphasis on the mechanisms of action, efficacy, and prospective advantages of silver NPs, this review attempts to give a thorough overview of the numerous biological applications of these particles. The utilization of silver NPs in diagnostics, such as bioimaging and biosensing, as well as their functions in therapeutic interventions such as antimicrobial therapies, cancer therapy, diabetes treatment, bone repair, and wound healing, are investigated. The underlying processes by which silver NPs exercise their effects, such as oxidative stress induction, apoptosis, and microbial cell membrane rupture, are explored. Furthermore, toxicological concerns and regulatory issues are discussed, as well as the present difficulties and restrictions related to the application of silver NPs in medicine. Full article

(This article belongs to the Special Issue The Synthesis of Antibacterial Nanomaterials and Their Biomedical Applications)

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10 pages, 4012 KiB

Open AccessArticle

Tuneable Red and Blue Emission of Bi³⁺-Co-Doped SrF₂:Eu³⁺ Nanophosphors for LEDs in Agricultural Applications

by Jovana Periša, Sanja Kuzman, Aleksandar Ćirić, Zoran Ristić, Željka Antić, Miroslav D. Dramićanin and Bojana Milićević

Nanomaterials 2024, 14(20), 1617; https://doi.org/10.3390/nano14201617 - 10 Oct 2024

Abstract

Tunable blue/red dual-emitting Eu³⁺-doped, Bi³⁺-sensitized SrF₂ phosphors were synthesized utilizing a solvothermal-microwave method. All phosphors have cubic structure (Fm-3m (225) space group) and well-distinct sphere-like particles with a size of ~20 nm, as examined by [...] Read more.

Tunable blue/red dual-emitting Eu³⁺-doped, Bi³⁺-sensitized SrF₂ phosphors were synthesized utilizing a solvothermal-microwave method. All phosphors have cubic structure (Fm-3m (225) space group) and well-distinct sphere-like particles with a size of ~20 nm, as examined by X-ray diffraction and transmission electron microscopy. The diffuse reflectance spectra reveal a redshift of the absorption band in the UV region as the Bi³⁺ concentration in SrF₂: Eu³⁺ phosphor increases. Under the 265 nm excitation, photoluminescence spectra show emission at around 400 nm from the host matrix and characteristic orange ⁵D₀ → ⁷F_1,2 and deep red ⁵D₀ → ⁷F₄ Eu³⁺ emissions. The red emission intensity increases with an increase in Bi³⁺ concentration up to 20 mol%, after which it decreases. The integrated intensity of Eu³⁺ red emission in the representative 20 mol% Bi³⁺ co-doped SrF₂:10 mol% Eu³⁺ shows twice as bright emission compared to the Bi³⁺-free sample. To demonstrate the potential application in LEDs for artificial light-based plant factories, the powder with the highest emission intensity, SrF₂: 10Eu, 20 Bi, was mixed with a ceramic binder and placed on top of a 275 nm UVC LED chip, showing pinkish violet light corresponding to blue (409 nm) and red (592, 614, and 700 nm) phosphors’ emission. Full article

(This article belongs to the Section Inorganic Materials and Metal-Organic Frameworks)

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21 pages, 5073 KiB

Open AccessArticle

Biodegradation of Heterogeneous Industrial Multi-Walled Carbon Nanotubes by Pro-Inflammatory Macrophages

by Alexander G. Masyutin, Ekaterina K. Tarasova, Daniil A. Samsonov, Galina E. Onishchenko and Maria V. Erokhina

Nanomaterials 2024, 14(20), 1616; https://doi.org/10.3390/nano14201616 - 10 Oct 2024

Abstract

Industrial multi-walled carbon nanotubes (ig-MWCNTs) make up the majority of carbon nanomaterials, and human contact with them is the most probable. At the same time, the biodegradation of ig-MWCNTs by phagocytes has not been studied—existing articles consider mainly laboratory-grade/functionalized MWCNTs (l-MWCNTs), in contrast [...] Read more.

Industrial multi-walled carbon nanotubes (ig-MWCNTs) make up the majority of carbon nanomaterials, and human contact with them is the most probable. At the same time, the biodegradation of ig-MWCNTs by phagocytes has not been studied—existing articles consider mainly laboratory-grade/functionalized MWCNTs (l-MWCNTs), in contrast to which ig-MWCNTs are a highly heterogeneous nanomaterial in terms of morphological and physicochemical characteristics. The aim of the present study was to analyze ig-MWCNTs’ biodegradation by proinflammatory macrophages. We focused on both extra- and intracellular ig-MWCNTs’ degradation. We analyzed biodegradation of two different types of ig-MWCNTs by human (THP-1) and murine (RAW264.7) macrophages. After 10 days of incubation, we studied nanoparticle localization within cells; isolated intra- and extracellular ig-MWCNTs were used for quantitative analysis. Ultrastructural and morphometric analysis were performed using transmission electron microscopy; electron diffraction was used for nanotube identification. To estimate chemical alterations, energy-dispersive X-ray spectroscopy and Raman spectroscopy were used. The study showed that both intra- and extracellular ig-MWCNTs undergo almost complete biodegradation, but in different ways: intracellular nanotubes become perforated and reduce to graphene flakes, while extracellular become thinner. We believe that the demonstrated variability in the destruction of ig-MWCNTs by cells suggests the possibility of creating nanomaterials with controlled biodegradation properties. Full article

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13 pages, 812 KiB

Open AccessArticle

Model and Energy Bounds for a Two-Dimensional System of Electrons Localized in Concentric Rings

by Orion Ciftja, Josep Batle, Mahmoud Abdel-Aty, Mohammad Ahmed Hafez and Shawkat Alkhazaleh

Nanomaterials 2024, 14(20), 1615; https://doi.org/10.3390/nano14201615 - 10 Oct 2024

Abstract

We study a two-dimensional system of interacting electrons confined in equidistant planar circular rings. The electrons are considered spinless and each of them is localized in one ring. While confined to such ring orbits, each electron interacts with the remaining ones by means [...] Read more.

We study a two-dimensional system of interacting electrons confined in equidistant planar circular rings. The electrons are considered spinless and each of them is localized in one ring. While confined to such ring orbits, each electron interacts with the remaining ones by means of a standard Coulomb interaction potential. The classical version of this two-dimensional quantum model can be viewed as representing a system of electrons orbiting planar equidistant concentric rings where the kinetic energy may be discarded when one is searching for the lowest possible energy. Within this framework, the lowest possible energy of the system is the one that minimizes the total Coulomb interaction energy. This is the equilibrium energy that is numerically determined with high accuracy by using the simulated annealing method. This process allows us to obtain both the equilibrium energy and position configuration for different system sizes. The adopted semi-classical approach allows us to provide reliable approximations for the quantum ground state energy of the corresponding quantum system. The model considered in this work represents an interesting problem for studies of low-dimensional systems, with echoes that resonate with developments in nanoscience and nanomaterials. Full article

(This article belongs to the Special Issue Fundamental and Applied Aspects of the Physics in Low-Dimensional Systems)

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10 pages, 3009 KiB

Open AccessArticle

Unsupervised Learning for the Automatic Counting of Grains in Nanocrystals and Image Segmentation at the Atomic Resolution

by Woonbae Sohn, Taekyung Kim, Cheon Woo Moon, Dongbin Shin, Yeji Park, Haneul Jin and Hionsuck Baik

Nanomaterials 2024, 14(20), 1614; https://doi.org/10.3390/nano14201614 - 10 Oct 2024

Abstract

Identifying the grain distribution and grain boundaries of nanoparticles is important for predicting their properties. Experimental methods for identifying the crystallographic distribution, such as precession electron diffraction, are limited by their probe size. In this study, we developed an unsupervised learning method by [...] Read more.

Identifying the grain distribution and grain boundaries of nanoparticles is important for predicting their properties. Experimental methods for identifying the crystallographic distribution, such as precession electron diffraction, are limited by their probe size. In this study, we developed an unsupervised learning method by applying a Gabor filter to HAADF-STEM images at the atomic level for image segmentation and automatic counting of grains in polycrystalline nanoparticles. The methodology comprises a Gabor filter for feature extraction, non-negative matrix factorization for dimension reduction, and K-means clustering. We set the threshold distance and angle between the clusters required for the number of clusters to converge so as to automatically determine the optimal number of grains. This approach can shed new light on the nature of polycrystalline nanoparticles and their structure–property relationships. Full article

(This article belongs to the Special Issue Exploring Nanomaterials through Electron Microscopy and Spectroscopy)

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Nanomaterials, Volume 14, Issue 20 (October-2 2024) – 12 articles

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